/**
 * Copyright 2006 gworks.com.au
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. (http://www.apache.org/licenses/LICENSE-2.0)
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed 
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for 
 * the specific language governing permissions and limitations under the License.
 *
 * <dhamma-message src="Atisha (11th century Tibetan Buddhist master)">
 * 	The greatest achievement is selflessness. The greatest worth is self-mastery.
 * 	The greatest quality is seeking to serve others. The greatest precept is continual awareness.
 * 	The greatest medicine is the emptiness of everything. The greatest action is not conforming with the worlds ways.
 * 	The greatest magic is transmuting the passions. The greatest generosity is non-attachment.
 * 	The greatest goodness is a peaceful mind. The greatest patience is humility.
 * 	The greatest effort is not concerned with results. The greatest meditation is a mind that lets go.
 * 	The greatest wisdom is seeing through appearances. 
 * </dhamma-message>
 */
package org.javaongems.runtime.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Properties;

import org.apache.commons.io.IOUtils;
import org.javaongems.runtime.lang.StringUtils;


/**
 * <p>Provides a convenient properties features that are not part of the jdk or
 * commons collections</p>
 * <p>Responsibilities:
 * <ul>
 * 	<li> converts a properties object into a string representation
 * 	<li> converts a string representation of properties into a properties object
 * </ul>
 * </p>
 * 
 * @author Ashin Wimalajeewa (ash)
 */
final public class PropertiesUtils {
	private PropertiesUtils() {
		// nothing to do.
	}

	/**
	 * Command that converts the properties object into a string using utf8 
	 * encoding. Note this string can later be re-parsed using toProperties
	 * method.
	 * 
	 * @param props - the source properties to write 
	 * @param header - the header description to prepend to the properties
	 * @return the utf8 string representation of the properties 
	 * @see #toProperties(String)
	 */
	static public String toString(Properties props, String header) {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		try {
			try {
				props.store(out, header);
			} finally {
				out.close();
			}
		} catch (IOException err) {
			throw new IllegalArgumentException(err.getMessage());
		}
		try {
			return new String(out.toByteArray(), StringUtils.UTF8_ENC);
		} catch (UnsupportedEncodingException err) {
			throw new IllegalStateException(err.getMessage());
		}
	}

	/**
	 * Command that converts a string representation of properties into a properties object
	 * @param propsAsStr - the properties rendered as a string
	 * @return the properterties object representation
	 */
	static public Properties toProperties(String propsAsStr) {
		Properties ret = new Properties();
		toProperties(propsAsStr, ret);
		return ret;
	}
	
	/**
	 * Command that converts a string representation of properties into a properties object
	 * @param propsAsStr - the properties rendered as a string
	 * @param props - the properterties object to write the properties into
	 */
	static public void toProperties(String propsAsStr, Properties props) {
		if (propsAsStr == null)
			return;
		try {
			InputStream in = IOUtils.toInputStream(propsAsStr, StringUtils.UTF8_ENC);
			try {
				props.load(in);
			} finally {
				IOUtils.closeQuietly(in);
			}
		} catch (IOException err) {
			throw new IllegalArgumentException(err.getMessage());
		}
	}
}
